Yes this is the exact reason. BoostBasic does not recognise 'float' data type. We have already fixed this problem and after this fix were able to use BoostC floating point library with BoostBasic. This fix will be available in the next release (or update)
Following help from Pavel, I can get the maths functions to work, but some of the comparison functions fail, namely: ge, gt, ge_quiet and gt_quiet.
For example, using "Extern Function float32_ge(a as float, b as float) as boolean", together with "result = call float32_ge(x1,x3)", where result, x1 and x3 are float type